Method and apparatus for continuous strip metal treatment



Nov. 20, 1951 J. s. NACHTMAN 2,575,074

METHOD AND APPARATUS FOR CONTINUOUS STRIP METAL TREATMENT Original FiledFeb. 18, 1959 s Sheets-Sheet 1 INVENTOR FigJA.

Nov. 20, 1951 r J. s. NACHTMAN 2,576,074

METHOD AND APPARATUS FOR CONTINUOUS STRIP METAL TREATMENT Original'Filed Feb. 18, 1939 i s Sheets-Sheet 2 INVENTOR Nov. 20, 1951 J; 5.NACHTMAN 2,576,074

METHOD AND APPARATUS FOR CONTINUOUS STRIP METAL TREATMENT Original FiledFeb. 18, 1939 3 Sheets-Sheet I5 INVENTOR Patented Nov. 20, 1951 METHODAND APPARATUS FOR CONTINU- OUS STRIP METAL TREATMENT John S. Nachtman,Youngstown, Ohio Continuation of application Serial No. 257,107,

February 18, 1939.

This

1946, Serial No. 675,897

'Ihisapplication is a continuation of my prior application for Methodand Apparatus for Continuous Strip Metal Treatment, filed February 18,l939,=SerialNo. 257,107, now abandoned, which was a continuation-in-partof my application for l manner that it can be collected in separatecoils of a desired length. 1

In one phase,- the invention especially pertains to the proper controland handling of metal strip being plated, and particularly, beingelectroplated. When I speak of strip, it should be understood that Ihave reference to any suitable form or shape of material and that theprinciples of the invention are not limited to any particular type ofmaterial; of course, a flexible metal material which has been generallydesignated as metal strip is preferable. It will also be appreciatedthat certain phases of the present invention deal with the feeding,tensioning, handling,

the joining and the separating of pieces of strip, while other phasesdeal particularly with a controlled continuous treatment of metal strip.

'Where plating or electrode position forms part 01' the continuousprocess, the strip may be of any suitable metal. The same, of course, istrue of the plated metal. However, for'purposes of illustrating theinvention, I have referred particularly to the electroplating of iron orsteel strip with tin. In carry-out such a plating process, strip issupplied to the plating line in reels or coils of fairly great length.The process of preparing the strip for plating, washing, drying, etc..is preferably conducted continuously, one length or strip being suitablysecured to another length of strip to form a continuous stripprogression for the treating or plating line. It will be apparent that anumber of strips may be fed through the apparatus or line at the sametime in multiple.

I have found that additional problems have arisen in connection with acontinuous treatment of strip from a commercial standpoint as com- 9Claims. (Cl. sue -2s) application June 11,

pared to a laboratory standpoint. That is, the length of stripundergoing treatment at one time will be greater in the former case andits velocity of movement should be relatively high, much higher thanpossible heretofore prior to the present invention.

Heretofore, movement of the metal strip through the cleanin pickling,and plating stages has been carried out solely by the pulling action ofa wind-up reel or its equivalent that operates at the end of the platingline. I have discovered that in using such an apparatus, the plating ofextremely thin strips or fine wires was not possible at high speeds,that is, I discovered that there was a progressive building up oftension in the strip and that this building up was particularly great inthe case of a long plating line which is, of course, required inconnection with high speed operation. high as well as unsuitable tensionof the strip being treated, as well as surging of the line, not onlytend to distort the strip but also to spoil the plating operation andthe coating provided thereby. That is, I discovered that there are anumber of factors involved in electroplating from the standpoint ofconveying or moving the strip continuously past or through the necessarytreatment zones that entered into the characteristics of the products aswell as the effectiveness of the individual and collective treatments.

I also determined that it is important thatsubstantially the same amountof metal should be deposited upon'each unit area of the strip and thatas long as the strip passes continuously through the plating line andapparatus at a uniform rate and the current employed in electrodeposition is constant, the plating thickness can be kept substantiallyuniform. In case the speed of the strip is varied, the electroplatingcurrent should be varied proportionally, and vice versa, in order toprovide a uniform deposit.

In view of the above and other considerations. it has been an object ofmy invention to provide new and improved procedure and/or, apparatus forplating suitable material such as metal strip.

Another object has been to provide a procedure and/or apparatus forcontinuous and uninterruptedtreatment of a plurality of suitable lengthsof strip metal or other suitable material.

Another object has been to provide procedure and/or apparatus forcontinuously and uninterruptedly moving strip through or past suitabletreatment zones and for automatically segregat- 3 ing suitable lengthsof the continuous strip thereafter.

A further object of my invention has been to provide new and improvedprocedure and/or apparatus for suitably tensioning and/or controllingstrip material while it is being suitably treated and/or fed.

A further object has been to provide procedure and/or apparatus forsuitably proportioning the tension, speed, and rate or treatment ofmaterial. parrlzilcularly, while continuously moving the mate A stillfurther object oi my invention has been to provide a commerciallypracticable continuous plating procedure for utilizing strip metal incoil form.

These and many other objects of my invention will appear to thoseskilled in the art from the description, the drawings, and the appendedclaims.

In the drawings Figures 1A, 1B, and 1C are side views in elevationpartially sectioned and diagrammatic, which when placed end-to-end fromright to left respectively, illustrate a preferred embodiment of myinvention.

Summarized briefly, I provide metal strip in coil form, continuouslyunreel a given piece of strip from its coil, and continuously subject itto suitable treatments. Means is provided, a slack producer, for storinga suitable length of the strip and for continuously paying it out whilethe trailing end of an exhausted coil is welded, or in another suitablemanner, secured to the leading end of a. second or new coil strip. Afterthe strip lengths of two coils have been thus. joined or secured, theslack producing means is operated to take up a suitable length of thestrip of the second coil in readiness for later Joining its trailing endto the leading end of a third coil. In this manner, suitable individuallengths of material are continuously fed or passed through variousplating operations which may include the steps of pickling,wet-mechanically cleaning. washing, electroplating, washing, and drying.

As it is advantageous to. collect the treated strip in suitable lengths,possibly of substantially the same length as the individual coils at thebeginning of the operation, I have provided apparatus that isautomatically operable to select strip of suitable lengths and to severth'eselected lengths and separately coil them. The operation ispreferably carried out in such a manner that the tension of the stripbeing treated ahead of the apparatus is maintained at the desired valueirrespective of other operation being done. That is, the tension of thecontinuous strip being severed and coiled into individual lengths isautomatically controlled in such a manner as to not adversely affect theprior operations of the continuous plating line.

In the plating operations, I preferably provide suitably selected drivenrolls that are interposed in such a manner as to suitably tension thestrip for preceding and succeeding treating operations.

The plating and/or pickling current employed is suitably proportioned tothe rate of movement.

or in other words, to the speed of the driven rolls in such a mannerthat a high efficiency and effectiveness of treatment is obtained. j

Further, in accordance with the present invention, the steps of joiningone coil to another,

. of continuously treating the strip, and of severing the strip andrecalling suitable severed lengths thereof, are all correlated in such aman- 1B, and 10, respectively. As shown particularly in Figure 1A, oneor more coils or reels of strip metal 4 are paid out from positions Iover suitable guide rolls 6 to the strip treatment line. In general, theillustrated layout includes, reading from right to left, a payout reelstand or support A. a guide table 13, a welding mechanism C, a guidetable D, a slack producer and surge control apparatus E, anelectrocleaning apparatus F, a wet-mechanical cleaning unit G,'a coldwater rinse bath H, a pickling vat I, a wet-mechanical cleaner J, anelectroplating means or unit K, cold and hot baths R and K,respectively, a drier L, a bridle stand or pull rolls M, a photoelectriccontrol unit N, a shearing unit 0, reel selector mechanism P, and awind-up reel unit Q.

In carrying out the invention, the strip 4 is taken from one of thereels 5, is guided by suitable guide rolls 6 through the welder C overthe table D to the pass of a pair of pinch rolls I of the slackproducing unit E. The strip is then guided over an idler guide roll 8 ofa primary, vertically-movable payout roll carriage III, over afixedly-positioned idler guide roll Lover an idler guide roll 8 of a.secondary, verticallymovable dancer-roll carriage 2|, and then out overa suitable guide roll 6 to unit F. In normal operation, the position ofthe strip 4 is indicated by the dotted lines beneath the carriage IIIwhile the secondary carriage 20 is in some suitable position such asshown in the drawing. The full line position of the strip shown inFigure 1A is the normal position during welding of the trailing end ofthe strip of one coil to the leading end of the strip of a second coil.

The lower pinch roll 1 is indicated as being driven bya suitable motorH9 which is constructed and arranged as will be hereinafter more fullyexplained to provide a desired tension or pull upon the strip adjacentthe entrance to the slack producer unit E. i

The payout roll carriage I0 is counterbalanced by a rope or cable iihaving a counterweight l3 and is guided over a suitable guide roll 6aand a driven roll or cable-driving pulley II. The pulley I2 is actuatedby a reversible payout motor I! to raise and lower the carriage It aswill be hereinafter more fully described. In like manner, the secondaryor dancer carriage 20 is counterweighted through the agency of a cableor rope H and counterweight 13; the rope ll leaves over pulley guide 6aand rheostat control pulley 22. The pulley 22 is operably connected toan arm of an adjustable rheostatll in such a manner that automaticcontrol is obtained over the pinch roll motor Ill and the payout motorI! in response to oscillation or rotation of the pulley 22, and thus,dependent upon the position of the dancer roll carriage 20. The carriageII maintains a substantially constant tension in the strip, movesvertically in response to operation of the loopproducing carriage l0,and eflectively "irons out line surges without transmitting them.

I The loop-producing carriage- It is provided,- as shown. with anextending switch-operating arm l4 that in its extreme upper positionopens a normally-closed payout switch II and that in its extremelowerposition closes a normally- 'open payout-start-limit switch is. In likemanner. the dancer roll carriage is provided with a switch operating arm2| that first opens a normally-closed emergency slow-down switch 24 andwhile holding this switch in such a position, opens an emergency-stopswitch 25. An emergency-stop-iimit switch I8 is positioned beneath thepayout roll carriage l0 and is moved from its normally closed (make)position to an open position (break). if and when the carriage ll movesto its extreme bottom-position.

The strip continuously leaves the slack producer E as a continuouslength having a suitable speed and tension. It is shown as thenintroduced into a suitable electrocleaning tank F having immersed anddriven contact rolls II and immersed and cooperating guide rolls i.Current is supplied by generator 32 that is preferably driven at aconstant speed by a motor 33; the generator 32 is electrically connectedwith the contact rolls iii and with a spray pipe assembly 3| positionedabove and below the strip 4. The current supplied by the generator 82may be varied in the conventional manner and is also preferably variedautomatically to properly correspond to the conditions of operation aswill subsequently be explained.

From the cleaning tank F, the strip 4 passes through a scrubber G havingcooperating pairs comprising driven brushes 3!, idler rolls 36, anddriven squeegee rolls 36a. Rolls 36 may be driven, if desired, by amotor H8. The sprays for water of suitable temperature have been indicated by the numeral 31. The strip is then conveyed through acold waterwash tank H, between driven tension roll b and a cooperating guide roll6, through a pickling bath 1, between driven tension roll 35 and acooperating roll 6, to a driven wet-mechanical cleaning unit J similarto the unit G previously described.

The strip 4 is now ready for'immediate entry into the electroplatingbath K and the operation is preferably carried out in such a manner thatthe cleaned strip will be covered with a coating of the wash fluid,preferably water, after it leaves the unit J until it enters the bath ofthe unit K. The number of plating elements, etc..

7 of the unit K have been reduced in the drawing IB, but it will beunderstood that any suitable number may be provided. The unit comprisesidle and submerged guide rolls 42 above which are operably-mountedcomplemental roll pairs which comprise upper, contact and driven rolls4., and lower, positioning rolls 4i. Motors ill actuate the rolls toprovide the necessary electrical contact with the strip and to preventan undesirable building up of tension of the strip during movementthrough the bath K. As shown. the rolls 40 are connected to one terminalof a pair of plating generators 44 that arev preferably driven at aconstant speed by motor 45;

and in this manner, the strip 4 is converted into. a cathode as itpasses in a multiplicity of loops through the bath of the plating unitK. Verti-.

cally-extending anodes 43 of plating material such as tin are disposedin the bath within the spaces ail'orded by the strip loops in such amanner that there are, in effect, two groups of anodes; one group willplate one side of the strip and the second group will plate the otherside.

tension and squeegee roll flb, cooperating with a guide roll- I. It thenenters and. is guided through cold and hot cleaning baths R and H bysuitable guide rolls 4; it is introduced into and leaves the baths byway of pinch roll pairs comprising a driven tension roll lib and a guideI roll 8.

The strip then passes through the drying unit L which may include adrier 41 and nozzles 44. and then enters the bridle stand apparatus M.The bridle stand apparatus or unit M is coordinated with a photo-cellunit N, a shear unit 0, a selector unit P, and a coiling, reeling orwrapping unit Q, in such a manner that the desired tension of the stripis maintained aheadof the bridle stand while at the same time a suitabletension and/or feed of the strip is provided following the bridle standduring the selection of suitable lengths of strip, the severance ofthose lengths. and the coiling of those lengths into suitable coils. Thebridle stand M is, in effect, set into operation through the agency ofthe photo-cell unit N. In this connection, I preferably punch a hole inthe strip after welding one coil toanother adjacent the unit C in orderthat a beam of light from the lanip ID on one side of the strip willpass therethrough and transmit energizing light to the photo-electriccell ii. The cell ll initiates a number of automatic operations. Ofcourse, it will be apparent that any other suitable means may beemployed in this connection for initiating the correlated operation ofthe units which will be hereinafter more fully explained.

The strip 4 after leaving the drier unit L is guided by roll I into thebridle stand M and over three rubber covered rolls III, 5i, and 52 thatserve to drive and tension the strip and to keep it in'check during thecutting and take-oil operations. Roll 60 is operably geared (see Figure1G) to the roll Ii. Rolls Ill, II, and i2 grip anddraw the strip; rollII is driven by a suitable motor 43-! that is preferably under automaticspeed control as will be explained later. A one-revolution mechanicalclutch 54 is mounted on the shaft II of the driven bridle-stand roll II.

Clutches of this character are per se well known.

being operable upon actuation to intercouple the clutch with the shaft55 for aperiod of a single revolution of the latter; the clutchthereafter returns to its initial position for subsequent actuation. Theclutch 54 is provided wit-h an arm 58 that is connected by a link to themagnetic core 51 of a magnetic solenoid 51a in such a manner that whenthe solenoid 51a is energized to lift its core 51, the arm I6 isoscillated to pro- 7 armor;

provided for confining movement in the plane of the strip 4. The otherends of the shear arms 60 carry shear blade supports 61 that areoperably mounted above and below the plane of the strip and have rollers62 for guiding them between a pair of horizontallyextending rails 69. Acompression spring is positioned between the upper and lower supports 6|normally to urge them apart or out of an operating position with respectto the strip 4. Pairs 01' cutting blades 63 are mounted upon the ad-Jacent opposite ends of the upper and lower supports 6| in such a mannerthat they can be thrust towards each other to cut a suitable size pieceout of the strip 4, preferably corresponding substantially to the areaof weld between the strip of two coils. Thus, the shearing actionpreferably is timed in such a manner that the overlapped and/or weldedterminals or ends of a pair of joined strips are cut in this operation.

A cam element 65 is pivotally mounted at B6 and is provided with a camface extending beyond the upper and lower rails 69 for operating theshear mechanism. The cams 65 are normally retained in abutment with afixed stop 68 by a tension spring 6! that is connected between the camand the stop. As the rollers 62 of the shear carriages 6| travel overthe cams 65 to the left. the latter are prevented from swinging by thestop 68 and the shear support carriage 65 and their associated bladesare thrust towards each other sufliciently to compress the springinterposed therebetween to cause the blades 63 to sever a section of thestrip. Return movement of the shear 63 to its original positionillustrated is permitted by the springs 61 without cuttin the strip asecond time; that is, the cams are permitted to turn about their pivotpoints 66 when the rolls 62 of the shear carriages are re turned totheir original position from left to right in the drawing in Figure 1C.The cams 65 are thus forced to swing counter-clockwise on their pivots66 until the rollers 62 have cleared them. The reel selector mechanismor unit P is operated or actuated by the gear 53 which is in mesh with alarger gear 86; the ratio is preferably two to one such that the gear 80will turn half a revolution upon each actuation of the one-revolutionclutch 54. A crank arm 8! is operably mounted on the gear 80 and ispivotally connected to a selector unit operating link 82; the turn,pivotally connected to a pivotally-mounted operating and strip-selectinglever means 83. As shown, the lever 83 has an upper portion thatterminates in a selector plate that can be swung to one or the other oftwo strip guiding positions as illustrated in full and broken lines ofFi ure 1C. In the full 'line (lower) position, the plate of the lever orselector element 83 cooperates with a guide roll 6 and stationary guides88 and 88 to guide and permit the strip 4 to pass to the lefthandwind-up reel 90a of the unit Q. In this position, the lower switchportion of the selector element 83 has moved the coil motor selectorswitch 85 to the position shown in such a manner that the motor 9211 isactuated to wind up the lefthand reel 90a. At the same time, theright-hand motor selector switch 84 is pressed to the full lineposition, by its compression spring opening the line to the armature ofthe righthand coil wind-up motor 92b. Thus, the righthand motor 92b andits associated coiler 90b are stationary at this time.

When the selector arm its "extreme right position,

83 has been moved to the 'leithand selector this axis to horizontalswitch 4| opens the armature circuit of the lefthand wind-up motor 82aand closes the armature circuit of the rlghthand motor 92b through theagency oi the rlghthand selector switch 84, see the dotted lineposition, 0! this latter switch. In this position, the deflector plateportion of the lever 83 is raised to intercept the oncoming severedstrip end and to direct it over guide plate 81 to the righthand coilingreel 90b. Actuation oi the selector mechanism P closely Iollows and istimed to the shearing step which takes place during the first quarterrevolution of the mechanical clutch. For each full cycle shearingoperation, there is thus only a one-halt cycle operation of theselecting mechanism. In the case of both of the coils 80a and Nb, a beltwrapper mechanism 8| .0! conventional design is operable to catch anoncoming end or a severed strip and to start it around the empty reel ordrum as it is turned by its motor 92a or 92b for reception of theelongated strips.- Such belt wrappers are well known and form per senopart of the present invention.

The actuating or motor drive for driving the various contact, pinch,and/or tension rolls by the numeral H8. The fields of the motors I It aswell as the fieldsot the wind-up motors 92a and 92b, of theslack-producer pinchroll motor I IQ, of the payout carriage drive motorof the bridle stand motor 63-1. and a sepalink is, in v 7 speed ofrately-exclted field 95 or generator 93 are sum plied with current by asuitable constant voltage generator HI, Figure 10, connected to constantvoltage supply lines 2 and H3. A constant speed motor H0 drives thegenerator III as well as a variable voltage generator H5. The arma tureof the variable voltage generator 5 is connected to the current supplylines Hi and III which, in turn, provide the current for actuating thearmatures of the motors H8, 1 l8. l9, and 63l. The separately-excitedfield vi the gemerator H5 is controlled by resistance I21 and controlrheostat 120 to vary the current supplied to the mains H6 and I". Itwill also be noted that the fields of the electrocleaning gen:- erator32 and of the electroplating generator armatures 44 are connected to thecurrent supply mains I I8 and H1 in such a manner that their fieldexcitation will vary in proportion to the the motors above-mentioned.

The armatures of wind-up motors 92 are sup-.- plied with current by agenerator 93 that is driven by a suitable motor 96 and has aseparately-excited field 95 and a shunt salt-excited field .84 and adiflerential series field 54a. A lefthand contactor mechanism 91, Figure1C, having three pairs or sets of contact points, controls the supply oiactuating current to the armature of the lefthand wind-up motor 921:from the generator 93 which is preferably driven at a constant speed anddelivers a normally constant horsepower output. As shown, it is providedwith differentiallycompounded field coils 94, 94a, and 95. The

. righthand contactor 98 is in like manner provided with'three pairs ofcontact points for controlling the supply ofcurrentrrom the supplygenerator 93 to the motor 921:.

The photo-cell control when the photo-cell II is energized by receiv-7'5 ing light from the source 10 through a hole in,

or through an intentionally placed irregularity on the strip 4, it willenergize a holding coil II of a control relay I2 that, in turn,energizes the solenoid 01' a time delay relay I9. When the time relay I9is energized, it will open a normallyclose contact TI and insertresistance 19 into the circuit feeding the field of the bridle standmotor 93--I and the separately excited field 99 of the wind-up motorgenerator 93. This will increase the pull on the strip exercised by thebridle stand motor 93-4 as applied to the rollers ll and 92 and willdecrease the pull on the right, or left, wind-up motor 92a or 92b, asthe case may be, to thus eflect a low tension pull (enough to take upslack) by the righthandreel 99b upon the strip that is to be sheared.That is, the throwing oi' the resistance I9 in the separately excitedfield 99 of the generator 93 will decrease the current supplied by it tothe wind-up motor 92a or 92b.

The contactor I2 on closing will also energize the coil of the solenoid91a to raise the magnetic core El and oscillate the arm 59 and producean engagement of the one-revolution mechanical clutch 54, which operatesthe shear as previously explained. Assume for the purpose of thisdiscussion that the strip is being fed to the lefthand coiler 99a andthat the selector switch 95 is closed to actuate the lefthand wind-upmotor 92a. Then, the strip 4 will be severed by the actuation of theclutch 54 and the shear mechanism the selector arm 93 will be moved tothe right by the operative engagement between the clutch gear 53 and theoperating wheel 99. The righthand movement of the selector arm 83 willcause the holding coil 98 to be de-energized and the holding coil I99 tobe energized. Thus, the switch contact points of the contactor 91 willbe opened and those of the contactor 99 will be closed to actuate thearmature oi the righthand wind-up motor 92b, and thus, the righthandwind-up reel 99b. Simultaneously therewith, the selector plate moves thecut end of the strip down along the guide 81. 4

During the time that the switch selector arm 33 is leaving switch 85 andis moving towards switch Starting 0r initiating the operation of theline The apparatus is started by first moving ad- Justabie arm of'startrheostat I29, see Figure 18, to contact point I2I. At this time. aresistance I21 is connected between the rheostat I29 and theseparately-excited field of the variable voltage generator H9. Theclosing or the contact point I2I directly connects the holding 0011 I29of a general line contactor switch I25 to the motor field current supplyline II3; the other side 01' the coil I29 is directly connected to theline H2. The energization ofthe general line contactor switch I29 closesits three pairs or sets of contact points, the left set of whichconnects the switch side of the armature of the generator III to themotor armature and generator field current supply line I H, the centerset of which energizes the separately excited fields of the platinggenerators 44 through the lines I I9 and I I 'I, and the right set oi.which connects the side oi. the relay coil I29 that was closed by therheostat I 29 to the line I I3 through an emergency stop contactor I29,Figure 1A. Thus, the contactor I29 will remain closed when the arm ofthe starting rheostat I29 is moved off point I2I to the left 01' Figure1B and suitably resistance-adjusted to provide a desired strength 01'field for the generator II9.

- It will be noted that the closing of the righthand switch points orthe contactor I29 also closes 84, both contactors 91 and 99 will be openand the armatures of both of the wind-up motors 92 will beole-energized. Mechanical interlocking means I M i provided forpreventing a simultaneous closure of both contactors 91 and 99, butpermitting a simultaneous opening of them. The opening of the switchcontact points of the lefthand contactor 91 will de-energize the relaycoil I3, the coil of the time delay relay l9, and the coil of the clutchoperating solenoid 51a. The coil of the time delay relay I9, however,will not close its contact 'II immediately, but will remain open for adefinite time period following the deenergization of its coil. This timedelay is sufllcient to keep the resistance I8 in the field of the motor93-I and the field 95 of the generator 93.

while the selector lever 93 moves from its lefthand position and closesthe righthand selector switch 84. This, of course, energizes the coilI99 of the righthand contactor 99 and closes the switch contact pointsthereof to insert the righthand wind-up motor 92b in the operatingcircuit. The leading end of the strip 4 upon reaching the reel 0! 99bwill be wrapped around the reel block several times by the belt wrapper9| and then the wrapper will be withdrawn. At this time, the

contact arm 11 of the time relay I9 will open,

short-circuiting the field resistance I8 and increasing the strength ofthe field oi the bridle the connection between the line I I3 and oneside of the light source I9, Figure 1C, and of the selector circuit Pwhich includes the switches 94 and and contactors 91 and 99. In otherwords, it will appear that the excitation of the field 99 of the wind-upmotor supply generator 93 will depend upon the position of the righthandpair of contact points or the contactor I25, and that the wind-up motors92a and 92b will be actuated depending upon the position or theselectorarm 93 to initiate the actuation of one of the wind-up reels 99a or 99b.The closing or the point I2I' of start rheostat I29, in addition toenergizing the armatures oi the various motors such as H9, H9, 93, and92, also, as previously set forth, energizes the fields oi. generators93, 44, and 32. After the starting has been accomplished, the arm of therheostat I29 may be moved along the resistance to control the voltage ofthe field oi. generator H5 to set it to provide a desired voltage forthe armatures of the various motors as well as for the fields of theelectroplating and electrocleane ing generators 44 and 32, respectively.9

Operation of continuous feeding while welding set of which connectopposite sides of the arma ture of a payout motor I9 to the currentsupply mains H9 and Ill. The motor 19 is thus actuated to turn thepulley i2 and raise the payout roll carriage I to provide a reserve orloop of the strip 4. When the payout carriage l0 reaches the top of itstravel, it will be stopped automatically by payout switch I which isopened by the extending arm I4.

After the strip c0115 is completely paid out, the operator will press astop-payout switch (break) button I35 that will de-energize holding coilI of a pinch roll control contactor I40; this, in turn, will disconnectthe armature of the pinch roll motor I I9 from the current supply lineH1. It will be noted that the left and center pairs of contacts ofcontroller I40 are of the make type while the righthand set or pair areof a "break" type; thus. the latter will make" at this juncture toenergize holding coil I45 of contactor I38 through line H3 and theclosed contacts of stop-limit switch I8. The actuation of holding coilI45 will, in turn, close three sets or pairs or switch contacts, thefirst two of which reverse the current supply leads H5 and H1 to thearmature of the payout motor l9 and the third or righthand set willclose the holding circuit in parallel with contacts I42. The payoutcarriage control motor l9 will thus be actuated in a reverse directionto lower the payout carriage I0, and to feed the strip to the platingline as needed by progressively decreasing the size of the loop beneaththe carriage. The dancer roll' carriage 20 will automatically regulatethe speed oi the payout motor I9 through the operative connection of thepulley 22 with the field current control rheostat 23 to give a uniformpayout of strip to the plating line. Push break switch I44 provides foran emergency stop of motor l9 when carriage I0 is being raised.

The operator will weld the leading endof a new coil of strip to thetrailing end of the exhausted coil at the welder C while the carriage I0is being moved downwardly. As the carriage I0 approaches its lowerposition, it will reclose the (normally open) payout-start-limit switchIt and current will flow from the supply line I It to the coil I of thecontactor I40 to energize the coil and close its first and second pairsof contacts (from left to right). Its right set I42 are opened. Theopening of the contacts I42 has no eiiect, as it is paralleled by theholding circuit on switch I45. The closing of the make pairs of contactsofthe contactor I40 connects the armature of the pinch roll motor H9 tothe supply line I", thus initiating its movement. It will be lowestposition, it will be stopped automatically by stop-limit switch I8. Thatis, the carriage strikes the switch I9 and breaks" or opens it. Shouldany emergency condition arise whereby noted that rheostat 23 alsocontrols the speed of the motor H9 would fail to start at the time thepayout carriage l0 recloses the payout start limit switch I 0, thecarriage I0 will continue on to the bottom and stop, and since the lineis receiving strip and no further strip can be paid out by the carriageI0, the dancer roll carriage 20 will lower automatically. As the dancerroll carriage 20 reaches the emer ency slow-down switch 24, itsextending arm 2| will break or open it, and this will, in turn,tie-energize emer gency slow-down contactor coil I30, opening itscontact points and inserting resistance I21, see Figure 1B, in the fieldof variable-voltage line current supply generator H5, see Figure 10;this will bring the strip driving motors H8, the pinch roll motor H9,the bridle stand motor 83-I, etc., down to a creeping speed and will cutdown the field energization of the generators 32 and 44 in proportionthereto. If the emergency is such that the dancer roll 20 continues tomove downwardly, its arm 2| will continue to hold the switch 24 open andadditionally will open or break" the emergency stop switch 25 whichwill, in turn, de-energize contactor coil I29. The opening of thelefthand portion of the contactor I28 through the de-energization oi!the coil I29 will, in turn, cause a de-energization of the coil I20 ofthe contactor I25 and an opening of the entire line circuit. Thus, thegenerators are deenergized and the motors are stopped. The plating lineonly can then be started by raising the dancer roll frame 20 to itsnormal operating position.

In accordance with a preferred operation, the pinch roll motor H9 aswell as the bridle stand motor 63-4 are normally driven to provide adrag tension. During severance of the strip at O, the motor 03-I isadjusted by field control 18 to increase its torque to provide a for.-ward pull on the strip 4; the wind-up motor 92a or 921) is changed froma forward to a substantially zero pull (enough to take up slack). It,therefore, follows that the shearing operation is accomplished underconditions of minimum tension. I haveiound to prevent tearing anddistorting of the strip and also to permit an uninterrupted continuationof the plating operations or line treating operations and to initiatethe coiling of a new section or length of the strip that is being fed.It is apparent that the automatic control of the present invention makespossible a high flexibility of operation such that the desiredarrangements can be carried out regardless oi the particular operationsinvolved. I have found that the strip can be tensioned properly duringthe treating operations and that line surges such as may ariseparticularly in a long line can be welded to the leading end of a newcoil at the unit C, the pin roll motor H9 is then preferably adjusted ineffect. to tension the strip or hold it back in the direction of itsnormal movement; this gives the welder an opportunity to attach quicklythe two coil ends together and thereafter normal operation again may beassumed.

Although for the purpose of illustration, I have applied my invention toan electroplating line and have used a particular type of layoutpreferably employing direct current roll-driving m tors for simplicityof control and operation, it will be apparent to those skilled in theart that other suitable arrangements and connections may be employed aswell as any suitable type of motivating means without departing from thespirit and scope of the invention as indicated in the appended claims.It will also appear that the present invention makes possible asubstantially complete automatic operation of a series of treating stepsupon a piece of material that is provided in suitable separate lengthsand that after treatment again may be cut and gathered into suitablelengths without disturbing the continuous operation of the treatmentline. It will also be apparent that the invention makes possible asuitable practicable control and tensioning that this is highlydesirable similar to that oi motors I".

13 of the strip on the basis of any particular treatment to which it isto be subjected 'at any point along the line, regardless of prior orafter types of treatments. In view of these andother considerations,- itis felt that the present invention shouldnot be limited to particulardetails and structural parts but that suitable modifications. additions,substitutions, omissions, etc, may be made without departing from thespirit and scope oi'- the invention. For example, it it is desired thatstrip be cut to length after treatment in the line, a leveller, flyingshear, and piler may be used in place oi reels "a and! and theirassociated apparatus. Obviously, in such a case, the bridle-stand motor"-4 will be adjusted to provide a forward torque, and leveller, shear,and piler motors will have connections I claim: 1.In a method ofcontinuously electroplating coiled discontinuous metallic strip withcoating of metal, the steps 01' unreeling said discontin ous metallicstrip from supply coils, joining e discontinuous strips end to end,conveying the Joined strips uninterruptedly under tension through a loopvariable in response to tension changes and then in a fixed path throughan electroplating operation by applying propulsive power to the stripafter said electroplating operation, automatically segregating theplated strip into discontinuous lengths and automatically recoiling saiddiscontinuous lengths, establishing a predetermined tension in the stripby.

applying power to the strip between the unreelingcoils and said variableloop, and automatically regulating the rate of unreeling strip bycontrolling the magnitude and direction of the tension-establishingpower in-response to variations in said variable loop due to tensionchanges,

2. In a method of continuously electroplating coiled discontinuousmetallic strip with coating of metal, the steps of unreeling saiddiscontinuous metallic strip from supply coils, Joining thediscontinuousstrips end to end, conveying the joined 'strips 'uninterruptedly undertension through a'loop variable in response to tension changes and thenin a fixed path through an electroplating operation by applyingpropulsive power to the strip after said electroplating operation,automatically segregating the plated strip into discontinuous lengthsand automatically recoiling said discontinuous lengths, establishing apredetermined tension in the strip by applying power to the stripbetween the unreeling coils and said variable loop,.accumulating aportion of'the unreeling strip in a storage loop between the point ofapplying the tension-establishing power and the electroplating operationwhile automatically regulating the rate of unreeling strip from saidcoils by controlling the magnitude and direction of thetension-establishing power in response to variations in said variableloop due to tension changes. stoppin a portion of the lmreeled stripbetween the storage loop and said supply coils and simultaneouslystarting paying out strip from the storage loop through theelectroplating operation, and automatically regulating the rate of suchpaying out from the storage loop in response to variations in saidvariable loop due to tension changes.

3; In a method of continuously electroplating a metallic coating onmetal strip supplied in discontinuous lengths irom coils requiring avarying pull, the steps or moving the strip from the coils l4continuously at predetermined speed in a fixed path through anelectroplating operation by applying propulsive power to the strip afterthe electroplating operation, establishing a predetermined tension inthe strip passing through said electroplating operation by applyingpower to the strip between said electroplating operation and said supplycoils, and automatically regulating the magnitude and direction of saidtension-estabiishing power in response to tension changes in the stripportion between the point of applying said tension-establishing powerand said electroplating Operation to compensate for the varying pull oithe supply coils and maintain said predetermined tension in said stripportion.

4. In the method as defined in claim 3, the step of applying propulsivepower to the strip within the electroplating operation in an amountequal to the power required to prevent a building up of tension in thestrip in said electroplating operation.

*5. In the method as defined in claim 3, the step of automaticallyregulating the electroplating current in the electroplating operation indirect proportion to the strip speed to give a uniform thickness ofelectroplated coating.

6. In a method of continuously electroplating metal strip supplied fromcoils, the steps of unreeling strip from saidv coils continuously at apredetermined speed through a fixed path in an electroplating operationby applying propulsive power to the strip after the electroplatingoperation, establishing a predetermined tension in the strip passingthrough said electroplating operation by applying power to the stripbetween said electroplating operation and said supply coils.accumulating a portion of the unreeling strip in a storage loop betweenthe point of applying said tension-establishing power and theelectroplating operation in preparation for attaching a new supply coilto the end of an unreeled coil, then adlusting said tension-establishingpower to stop the strip momentarily for attaching said new coil andsimultaneously starting paying out strip from said storage loop, andthen while starting unreeling from said newly attached coilautomatically regulating said tension-establishing power in response totension changes in the strip portion between the point of applying powerand said electroplating operation.

7. In apparatus for continuously electroplating continuous strip metal,an electroplating unit for continuously electroplating the moving strip,means for propelling the strip continuously under tension atpredetermined strip speed from separate coils through the electroplatingunit, motor drive means for paying out the strip from the coils to saidelectroplating unit, a movable carriage for maintaining a variable loopin the strip between the payout drive means and the electroplating unit,a movable strip storage carriage between thepayout drive means and theelectroplating unit, means for driving selectively said storage carriageto create a storage loop and to pay out strip therefrom, and meansoperatively connecting the storage carriage drive to said variable loopcarriage for automatically regulating the rate of payout from thestorage loop in response to variations in the variable loop due totensionchanges therein.

8. In apparatus for treating a continuous length of metal strip, asupport for holding a coiled length of metal strip, pull rolls spacedfrom said support for pulling strip from said support through saidapparatus, electroplating means between said pull rolls and saidsupport, a first cleaning means between said electroplating port and thefirst cleaning means for applying drag tension to said strip,,weldingmechanism adjacent said support for joining successive lengths of metalstrip to form a continuous strip, control means for stopping saidstripat said welding mechanism during the joining of successive lengths, saidpull rolls and motor withdrawing strip from said storage loop andpulling said strip through the first cleaning means, electroplatingmeans and second cleaning means at substantially constant speed whilesaid strip is stopped at said welding mechanism and means following saidpull rolls on the discharge side opposite said support for cutting saidstrip into predetermined lengths while said strip is .being continuouslymoved by said pull rolls through said first cleaning means,electroplating means and second cleaning means.

, 9. A method of electroplating a continuous length of metal strip,comprising essentially the steps of supplying metal strip 'indiscontinuous lengths, then welding such lengths of strip together endto end with good contact between successive lengths to form a continuousstrip, then forming a storage loop of the continuous strip, thencleaning the continuous strip, then electroplating the cleanedcontinuous strip, then cleaning the electroplated strip, pulling saidstrip through said first cleaning, electroplating and second cleaningsteps continuously and at substantially'constant speed, stopping theportion of said strip being joined during the welding operation whilewithdrawing strip from said storage loop, applying drag tension to saidstrip between the supply and the first cleaning operation, con-.tinuously moving the strip through the first cleaning, electroplatingand second cleaning operations under predetermined tension and cuttingthe cleaned electroplated strip into predetermined lengths 'whilecontinuously moving said strip through the first cleaning,electroplating and second cleaning operations.

JOHN S. NACHTMAN.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,120,191 Gibbs Dec. 8, 19141,242,695 -Hood Oct. 9, 1917 1,517,910 Kirsohner Dec. 2, 1924 1,533,447Newman Apr. 14, 1925 1,811,522 Shover et al June 23, 1931 1,928,409 CoeSept. 26, 1933 1,991,817 Nachtman Feb. 19, 1935 2,007,614 Prentice July9, 1935 2,009,856 Otis et al July 30, 1935 2,052,255 Shoulte Aug. 25,1936 2,066,565 Iverson Jan. 5, 1937 2,075,332 Antisell Mar. 30, 19372,076,969 Sieger Apr. 13, 1937 2,201,417 Webster May 21, 1940 2,238,667Wales Apr. 15, 1941 2,240,265" Nachtman Apr. 29, 1941 2,266,330 NachtmanDec. 16, 1941 2,325,401 Hurlston July 27, 1948 2,459,674 Nachtman Jan.18, 1949 FOREIGN PATENTS Number Country Date 427,436 Germany Apr. 13,1926 279,787 Great Britain Sept. 6, 1926

1. IN A METHOD OF CONTINUOUSLY ELECTROPLATING COILED DISCONTINUOUSMETALLIC STRIP WITH COATING OF METAL, THE STEPS OF UNREELING SAIDDISCONTINUOUS METALLIC STRIP FROM SUPPLY COILS, JOINING THEDISCONTINUOUS STRIPS UNINTERRUPTEDLY UNDER TENSION CHANGES AND THEN IN AFIXED PATH THROUGH AN ELECTROPLATING OPERATION BY APPLYING PROPULSIVEPOWER TO THE STRIP AFTER SAID ELECTROPLATING ELECTROPLATING OPERATION BYAPOPLYING PROPULSIVE POWER TO THE STRIP AFTER SAID ELECTROPLATINGOPERATION, AUTOMATICALLY SEGREGATING THE PLATED STRIP INTO DISCONTINUOUSLENGTHS AND AUTOMATICALLY RECOILING SIAD DISCONTINUOUS LENGTHS,ESTABLISHING A PREDETERMIED TENSION IN THE STRIP BY APPLYING POWER TOTHE STRIP BETWEEN THE UNREELING COILS AND SAID VARIABLE LOOP, ANDAUTOMATICALLY REGULATING THE RATE OF UNREELING STRIP BY CONTROLLING THEMAGNITUDE AND DIRECTION OF THE TENSION-ESTABLISHING POWER IN RESPONSE TOVARIATIONS IN SAID VARIABLE LOOP DUE TO RENSION CHANGES.